Milk line systems of dairy farms should be cleaned periodically to prevent milk discharged by the milk line system from being contaminated. With conventional milking machines, the milk line system is cleaned after the herd has been milked. However, with an automated milking system wherein the milking is accomplished with a milking robot, the milk line system is cleaned after a predetermined period of time has elapsed or a predetermined number of animals has been milked. Furthermore the milk line system may also be cleaned when it has been ascertained that milk produced by an animal which is infected with mastitis is being discharged by the line.
The cleaning of the milk line system is divided into three phases which comprise: the pre-rinsing, the main cleaning and the post-rinsing. The pre-rinsing serves to remove the milk residues as much as possible from the lines and the equipment prior to the main cleaning. Consequently, the main cleaning will require less detergent or other cleaning materials. To achieve this, the pre-rinsing step should not be a circulation rinsing. For the pre-rinsing step the water temperature is in the range of 40° C. to 60° C. The pre-rinsing step is succeeded by the main cleaning step. The main cleaning step serves to clean and disinfect the milk line and the milking equipment. This result is obtained by circulating cleaning fluid through the lines and the milking equipment. The main cleaning is normally effected with an alkali having a cleaning and disinfecting function. To avoid formation of scale in the milk line system, said system is normally further cleaned from time to time with an acid. With the acid, scale formed in the milk line system, such as on the electrodes of a milk conductivity sensor, can be dissolved and thus removed from the milk line system. After the main cleaning, the milk line system is normally cleaning by a third step of post-rinsing. This is to prevent residues of the cleaning fluid from coming into the milk. The post-rinsing is generally effected with tap water and the post-rinsing water should preferably not be circulated.
In practice the cleaning of the milk production equipment including milk lines is not carried out correctly as a result of which the equipment and lines are cleaned insufficiently and consequently the germ count of the milk often more than doubles. This may be caused by an insufficient quantity of alkali or acid, or by the insufficient post-rinsing, or by the fact that certain places are not reached by the cleaning fluid, because, for example, a tube is pinched off.
The invention is to provide a method, in which the above-mentioned drawbacks do not occur or are of at least minimized to a considerable extent.